Md. oyster season is nearing dismal end

Second-worst catch on record blamed on 2 parasites, drought

March 26, 2002|By Heather Dewar | Heather Dewar,SUN STAFF

Maryland's oyster harvest for the season that ends Sunday is expected to be only 120,000 bushels - about one-third of last year's catch and the second-worst since recordkeeping began in 1870, state fishery managers say.

A state scientist blamed two oyster parasites, MSX and Dermo, which thrive when Chesapeake Bay waters become super-salty.

"Both of them are worse when we get higher salinity, and we've now had two, going on three years of drought," said Stephen Jordan, director of the state's Cooperative Oxford Laboratory. "Salinity has gone up to near-record levels in many parts of the bay."

This year's poor harvest, he said, can be traced to last summer's drought, when about 40 percent of Chesapeake Bay oysters died; the normal death rate is about 30 percent. As the drought deepens, the prospects for next season are not encouraging.

"If salinity continues to stay high through the winter and spring, we will probably see more mortality," Jordan said.

Many watermen are getting out of oystering. The number working Maryland waters has fallen from about 900 last year to about 600 this year, said John Surrick, a spokesman for the state Department of Natural Resources.

"They're striped bass fishing, and some of them ... left to get other jobs" on land, said Larry Simns, president of the Maryland Watermen's Association. "Everybody's doing what they have to do to get by.

"We're hurting, and it's going to be worse next year."

First documented in the Chesapeake in the 1950s, MSX and Dermo began ravaging bay oysters nearly 20 years ago. The statewide harvest sank below 1 million bushels in 1986-1987 and has never come close to that level again.

The all-time low, a dismal 80,000 bushels, came in 1993-1994. Last season's catch was about 348,000 bushels, DNR records show.

Oysters seem to reproduce best in salty water, but the parasites thrive in the same conditions.

Jordan said it seems to take two drought years in a row for salinity levels to drop enough to allow MSX to spread. Normally, it's found no farther north than Tangier Sound, but this season it's been documented in Eastern Bay near the Bay Bridge, he said. Dermo is normally present throughout the bay, but it intensifies when salinity climbs, he said.

The oysters' plight is harming the entire bay restoration effort.

Scientists estimate that a healthy adult oyster filters up to 30 gallons of water a day, removing pollutants and restoring water clarity. The shellfish were once so abundant that they cleansed the bay's entire volume of water once every few days, experts believe. It takes today's depleted population nearly a year to do the same thing.

One goal of the bay restoration effort is to increase the number of Chesapeake oysters tenfold by 2010. Scientists think that might improve water quality enough to bring back lost sea-grass meadows and enrich oxygen-starved areas that are now devoid of life.

Schoolchildren and community groups have become dedicated oyster farmers. But the effort has been thwarted by the stubborn parasites, which are not harmful to humans but can kill oysters.

One state senator said the dismal harvest would intensify local interest in an Asian oyster, Crassostrea ariakensis, which looks and tastes like the native bay oyster but is apparently resistant to the two diseases.

In Virginia, where salinity levels are higher at the bay's mouth, the oyster harvest fell to 20,000 bushels last year. Scientists there want to introduce the Asian bivalve into the bay. But Maryland and federal scientists say it's important to study ariakensis first to make sure the introduction won't do unintended harm.

"There's not much hope out there," said Sen. J. Lowell Stoltzfus, a Somerset County Republican. "I think it's time to push on" with studies of the Asian oyster.

But Jordan said it's too soon to give up on the native oysters. State researchers are raising about 50 million young oysters in hatcheries and returning them to the bay. Their goal is to add 100 million hatchery-raised oysters to bay waters each year, which should be enough to counteract the effects of disease, he said.

"Nobody's throwing up their hands on this situation," Jordan said. "I think the native oyster has enough resilience that it has a lot of potential for recovery."

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